Portable humidifier



FIG. 1 is a front right perspective view of a portable humidifier;

FIG. 2 is a right side elevational view thereof the opposite side being a mirror image of that shown;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a portable humidifier, as shown and described. 